Abstract Recent studies by our group have revealed that the neuronal gene Arc, a master regulator of synaptic plasticity and information storage in the brain, acts as a repurposed retroviral Gag protein that forms capsids with the capacity to transmit genetic information between cells. These findings lead to a paradigm shift in the way we view both mechanisms of cognition and more generally how cells can signal to each other. This transformative R01 application will address these questions using a synergistic team of neuroscientists and virologists who will apply their expertise to Arc, intercellular gene transmission, and neuronal development. We will determine what genetic messages are transferred between neurons in Arc particles, how these particles enter ?target? neurons to deliver their RNA cargo to cell cytoplasm, and how delivery of this cargo influences the neuronal and synaptic processes that underlie memory and cognition. The methodologies to address these questions, as well as the potential impact of the answers, make this application ideally suited to the transformative R01 mechanism.